Communication system



y 1932- H. M. LEWIS COMMUNICATION SYSTEM I Original Fild June 15, 1927 4 Sheets-Sheet 1 QQR 1km INVENTOR. 15. I 6Z0 z's,

ATTORNEY..

May 31, 1932 H. M. LEWIS 1,861,135

COMMUNICATION SYSTEM Original Filed June 15. 1927 4 Sheets-Sheet 2 w S R Y K 0 U] [i F 03 Q3 Q7 Q7 J l %i Q 5 3 a? N & I: E m

. INVENTOR. ff/Zleza 25,

BY 6' d ATTORNEY May 31, 1932. V H. M. LEWIS COMMUNICATION SYSTEM Original Filed June 15, 1927 4 Sheets-Sheet 3 INVENTOR. flmlewzs,

A TTORNEY 4 Sheets-Sheet 4 fi m INVENTOR.

d ATTORNEY H. M. LEWIS COMMUNICATION SYSTEM Original Filed June 15. 1927 May 31, 1932.

L Umrs STATES Patented May 31, 1932 HAROLD M. LEWIS,-OF DOUGLASTON, NEW YCRK, ASSIGNOR, BY MESNE ASSIGNMENTS, TO WIBE-D RADIO, INCL, OF NEW YORK, N. Y., A CORPGBATION OF DELAWARE COMMUNICATION SYSTEM Application filed 1 15,1927, Serial My invention relates broadly to electrical communication systems and more particularlyto an alternating-current signal transmission and reception system.

One of the objects of my invention is to provide a system of communication whereby transmission of signaling energy may be eifected to a selected receiving station only when that receiving station is in condition to receive the signaling energy.

Another object of my invention is to providea cooperative system of intercommunication between transmission and receiving stations wherein both the transmission and receiving stations cooperate to produce the signalin currents which may be modulated ormodi ed at the transmitter for rendering the signals intelligible at the receiver.

Other and further objects of'my invention reside in the cooperative arrangement of circuits between transmission and receiving apparatus, as will be more fully understood from the specification hereinafter following by reference to the accompanying drawings in which Fig. lis a theoretical diagram illustrating the principles of my invention applied to a ciplesof my invention; and Fig. 4 shows the,

cooperative transmitter and receiver circuits of my invention applied to a space radio channel in which a different signaling frequency is transmitted in eaclrdirection simultaneously for controlling the circuits. at each terminal station.

Referring to the drawings in detail, in

Fig. 1 reference character 1 designates one terminal station and reference character 2 designates a cooperating station connected by line wires Y and 'X. Terminal station 1 includes the electron tube 3 having its inputcircuit connected to the line wire system Y and its output circuit completed through inductance l and high potential source 5. The cathode of tube 3 is heated from battery6.

The high potential battery 5 is by-passed 'No. 199,092. Renewed Augu t 1, 1931.

by means of condenser ,7 to permit thees- I tablishment of high frequency oscillations. The output clrcuits l, 5, 7 are rendered ineffective forproducmgany voltage efl'ect. on the input circuit of tube 8 directly byreason of the arrangement of the neutralizing circuit including the portion of inductance 8 and the condenser 9. 4 I have indicated-a shielding 1O preventing any magnetic I influence between the. output and input 'circuits of the tube 3.. At station 2 the electron tube 11 is similarly arranged with its input circuit connected to line wire system Xand its output circuit including portion of inductance l2 and high potential battery 14: shunted by by-pass condenser 15. Thecathode of tube 11 is heated from battery 16. A neutralizing circuit including condenser 17 and portion of inductance 18'are arranged for preventing any direct influence of the output circuit upon the input circuit of tube 11. Magnetic coupling between the input and output circuits is prevented by, suitable shielding represented at 19. The output circuit of the tube 11 is connected'to the line wire system Y by means of inductance 20 which couples with inductance 12. The output circuit of electron tube 3 is connected to line wire system X by means of inductance 21 which couples with inductance 4. It will be clear that by reason of isolationof the input and output circuits of the tubes at each terminal station neither tube can in itself be a generator of oscillations but cooperative ly the system will generate oscillations of a frequency depending upon the constants of thecircuit. The interconnecting wires Y and I tenuation of the lines the circuit will oscil- I late at a common or carrier frequency. 'A modulating signal such as voice frequency current will affect the carrier at allparts of the circuit so that a voice modulation at station 1 will be efi'ectiveat station 2 and vice" versa. The carrier frequency is cooperatively generated by the communicating stations.

In Fig. 2, I'have illustrated one of the pracsystem. The electron tube 3 at terminal station 1 is shown arranged in an oscillator circuit with'the input "circuit thereof provided with a-con'denser 23 for predetermining the resonant or oscillating frequency. The out put circuit is prevented from regenerating with respect to the input circuit.

The function of the hybrid coil is to prowide 29. bridge form :of balance (neutralizationi) :bebweenthe output circuit of the electron'tube'and its own input,.and at the same fll'lme ualdo w incoming signals from'the line to tlfiect. the input circuit andallowithe output of the 'tube :to be applied to the line. The ii dance of the :line is in one leg of the tbrldgenmd is balanced'by BN in another leg. 'Ehe' input of the electron tube is therefore connected to points which are conjugate to the :points across which the :output voltage is up lied. The .output of station 1 is thus lefie ive-only upon the input of station 2 and the ontput orfsmtionfl is onlyeeflective upon the'input ofstation 1. "I have illustrated a modulation circuit including microphone .24, source of potential 25, transformer system flfi and electron tuhe system :27 for controllin g tl1e=operatim1 of :tliexoscillator system 1. A ftfle ihone receiving circuit has been represented at '28 including telephones '29.

as the terminal station :2 :a hybrid coil system is represented at 30 with which the circuits of :electron tube 31 are associated. l he input circuitofelectrontube 31 is tuned by means of variablecondenser 32 and consects acrossfthe line system as shown. 'Regeneration between the input and output circuits of electron tube 31 is prevented. A modulation system :is provided for the oscillator 3'1 which comprises microphone 33, eource df'potential 34,-trans-iiormer system 35 and electron tube 36.- The output circuit of electron tube 36 is coupled with the oscillater system for controlling the operation thereof. A telephone receiver circuit is shown at 37 :to'w h'ich is connected the teleflnme receiver 38. Due to the rectifying ectionmf the tubes the signal currents will bee-eproducedat both'termina'l stations 1 and 2. l ke two stations land 2-are so connected flmt'they cooperateto generate acarrier frequency determined by the constants of the circuityand voice frequency modulating currents operate to produce the side bands or modulate the carrier wave. I

In Fig. 3 YIha-ve illustrated the application of my invention to a space radio system 'vihere'terminal stationsl and 2 are provided loop antennae represented at 39, 40, 41

tion 1.

' cuit may be tuned by means of condenser 44. By reason of the magnetic coupling normally existing between the loops 39 and 40 of terminal station 1 and the normal ten- 'dency of capacity feedback therebetween, I

provide a counter feed-back system 45 including a transformer, the winding 46 of which is connected in series with the receivingv loop circuit 39, and the winding 43 of which'is connected in series with the transmitting loop circuit 40. The eifect ofthe output circuit of tube 3 upon the input circuit thereof is therefore neutralized at the .terminl sta- The distant cooperative station 2 is arranged in a manner similar to the arrangement of circuits at terminal station 1. The transmitter branch of the terminal station 2 including loop 42 is .tuned by means of condenser 47. For preventing 'the feedback of energy locally at terminal station :2, I provide a counter feed-back system represented at 48 including one winding 49 in circuit with the receiving loop 41 and anotherwinding 50 in circuit with the transmitting loop 42. The output circuit of one station is thus effective upon the input circuit of a distant station and vice 'versa, so that the system is a cooperative generator of .a common carrier, and as before signaling currents can be applied for modulation of the common carrier at either or both stations, and reception or detection of the signals acmission medium is the ether or space. The feed-back necessary to overcome the attenuation of the medium must be greater, just as usual radio transmission must be more powerful than wire transmission. his clear 3 95 tem 39 cooperates with loop system 42 while loop system 40 cooperates with loop system .ln Fig. 4, I have shown one application complishcd at each station. Here the 'transl! 7 frequency being used at the other station for transmitting.

Station #1 includes an antenna-ground circuit 5152 with a tuned input circuit represented at 53 having a rejector circuit 54 therein. The circuit 53 connects with the input circuit of a detector tube 55 which is acted upon by the local oscillations derived from the oscillator 56. The resultant frequency is impressed upon the amplifier circuit 57 and then upon the input circuit of a second detector58 for operating the tel phones 59. The transmitter is shown as including the microphone control circuit heretofore concerned in connection with Figs. 2 and 3, the electron tube 27, and the electron tube system 60, the output circuit of which is coupled to the antenna-ground circuit through winding 61. The oscillations of the electron tube system 60 are controlled from of the output or transmission part from the input or receiver part. As lndicated'at station #1, one resonant period of the antenna which forms the input circuit to the detector 55 is for an incoming wave f of for example 1000'kc. and there is also associated with the input of 55. a local source 56 of oscillations f of kc. The output of then has in addition to the frequencies impressed upon the input also the sum and difference frequencies f, f and 'f f or 1020 kc. and 980 kc.

The input of tube 57 selects in this case the difference frequency 980 kc. and supplies it to twosources; to the second detector 58 for detection of signaling currents and to the power amplifiers 63 and which apply it' as a transmitting frequency to the antenna. The microphone 24 voice controls a modulator tube 27 to modulate the outgoing 980 kc.

wave. 1

At station #2, a similar arrangement of circuits is provided where the antennaground circuit 6465 connects to a circuit 66 wherein a rejector circuit 67 is connected. A detector 68 is provided for cooperating with the local source of oscillation 69, the resultant of which is. impressed upon. thetuned amplifier-circuit 7 0. The output of amplifier 7'0 isdivided and'supplied through winding 71.to the power amplifier 72 and also to thetuned input circuit of the detector, 7 3 for actuation of they telephone receivers 74. The output of the power amplifier 72 leads to the power amplifier 75 for controlling the supply of high frequency energy to the antennaground circuit 64-65 through coupling coil 7 6; At. station #2 it is 980 kc. that is being received and the same frequency f of 20 kc.

that is'used as a heterodyne or modulator to produce in the output of 68 of station #2, the sum frequency of 1000 kc. and difi'erence put of selects the sum frequency of-1000 kc. supplying it to the detector 73 and also to the power amplifier tubes 72 and 75 so at this station 1000 kc. is radiated. It will be clear. from the previous figures that in order I that station #1 may radiate 980 kc. and station #2 may radiate 1000 kc., the two stations must cooperatively generate and this generating will function if each station offers sufiicient amplification in its circuit to overcome the attenuation-of the .transmission medium.

It will be understood that'the circuit arrangements at'stations 1 and 2 are such that while station 1 is transmitting signaling energy, at say 980 kc., which is being received at station 2, station'2 is also'radiating energy, at say 1000 kc., which is being'received at station/1. For the purposes of explaining my invention, I have indicated by notes on the official drawings these relative values, but it will, of course, be understood that these valuesare merely illustrative and are not to be taken in the limiting sense.

Various modificationsof my invention will be apparent to those skilled in the art,-and while I have described my invention in certain of its preferred embodiments, I desire that it be understood that no limitations are intended other than are imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patentof the United States is as follows:

.1. In anintercommunication system, transmitting andreceiving stations, means at each of said stations for cooperatively generating high frequency oscillations, and means at each station for preventing the generation of oscillations at said stations independently of the cooperative effects of said other station said last/named means comprising a coupling arrangement by means of which the output and input circuit of said high frequency oscillation generating means are coupled together to suppress self excited oscillations in said oscillation generating means. I

2. In an intercommunication system a pair of communicating stations, means at each of frequency of 960 kc. At this station, the insaid stations for cooperativel generating high frequency oscillations, sai means having input and output circuits, and means at each station for preventing the generation of oscillations independently of the effects of the other cooperating station said last named means comprising inductance coils in the input and output circuits of said high frequency oscillation generating means said inductance coils being coupled together to suppress self excited oscillations in said oscillation generating means.

3. In an intercommunication system, com.- prising a plurality of stations, an electron 5 tube system at each of said stations, said electron tube system including input and output circuits, with the output circuit of the elec-' tron tube system at one station arranged to affect the input circuit of the electron tube a system at said other station for establishing oscillations by the cooperative efiects of said electron tube systems and means for preventing the electron tube system at each of the stations from generating self excited oscillations, said last mentioned means comprising inductance coils in the input and output circuits of each electron tube system, coupled together in counter-feedback relation.

4. In an intercommunication system a plurality of stations, each of said stations ineluding an electron tube system having input and output circuits, means for electrostatically and electromagnetically isolating the output circuit from the input circuit of the 1, electron tube system of each station, and

means for afiecting the output circuit of the electron tubeisystem at one station by the in put circuit of the electron tube system at the other station, with the output circuit of the electron tube system at said last mentioned station connected with the input circuit of the electron tube system at said aforementioned station for the establishment of high frequency oscillations by the cooperative effects of y 5 said stations.

,5 counter-feedback relation whereby self-excited oscillations in each of said units are suppressed, the input circuit of each unit being excited from the oscillations received from the output circuit of another unit.

HQ 6. In a communication system, a plurality of stations each adapted to transmit and receive, an electron tube system for each of said stations, input and output circuits for each of said electron tube systems, means for elec- -fi trostatically and electromagnetically' isolat-.

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